guix config with NetworkManager WiFi connection password

(define (vii-network-manager-connection-service-activation config)
  (let ((src (assoc-ref (current-source-location) 'filename)))
    #~(begin
    (use-modules (guix build utils)
             (ice-9 match))
    (mkdir-p "/etc/NetworkManager/system-connections")

    (for-each (match-lambda ((filename contents)
                 (let ((f (string-append "/etc/NetworkManager/system-connections/" filename)))
                   (call-with-output-file f
                   (lambda (p)
                     (format p "# vii-network-manager-connection-service-activation ~a ~a~%" #$src (strftime "%c" (localtime (current-time))))
                     (display contents p)
                     ))
                   (chmod f #o600))))
          `#$config
          ))))

(define vii-network-manager-connection-service-type
  (service-type
   (name 'vii-network-manager-connection-service)
   (description "Copies WiFi password to network manager system connection with proper 0600 permissions so that NetworkManager does not ignore them")
   (extensions
    (list (service-extension activation-service-type vii-network-manager-connection-service-activation)))))



; Example
    (service vii-network-manager-connection-service-type `(
                               ("HOME-viiguix.nmconnection"  "[connection]
id=HOME
uuid=df0b2685-d198-42de-b8fb-9b9fa2ea711c
type=wifi
permissions=

[wifi]
mode=infrastructure
ssid=HOME

[wifi-security]
auth-alg=open
key-mgmt=wpa-psk
psk=home

[ipv4]
method=auto

[ipv6]
addr-gen-mode=default
method=auto

[proxy]
")))